INTRODUCTION

1
OROGRAPHIC UPLIFT EFFECT AT HEIBERG FOREST IN
TULLY, NY Nicole Kadey, Heather Colagiovanni,
Matt Conlon, Dr. T. Endreny FOR 338 Meterology
Course, 148 Baker Hall, SUNY College of
Environmental Science and Forestry, Syracuse, NY
13210
INTRODUCTION An interesting aspect of weather is
rainfall, and its variance from one place to
another. When mountains are nearby, the rainfall
amounts can vary significantly within a small
distance. There are two basic effect on
precipitation caused by mountains. The first is
the orographic effect and the rain shadow.
Orographic is the lifting of air over a
topographic barrier. Clouds that form in this
lifting process are called orographic clouds.
The orographic effect happens on the windward
side of a mountain. The rainfall increase
dramatically as you move farther up the mountain
on the windward side. The rain shadow effect is
where precipitation amounts drop significantly on
the leeward side of a mountain. Source
USA TODAY research by Brian Brinch graphic by
John Herne HYPOTHESIS Ho The amount of rainfall
on the windward side of a mountain, in the same
sampling location, but different elevations are
the same. Ha The amount of rainfall on the
windward side of a mountain, in the same sampling
location, but different elevations increases at
higher elevations on the mountain. GOVERNING
THEORIES Orographic uplift occurs when air is
forced to rise because of the physical presence
of elevated land. As the parcel rises it cools
as a result of adiabatic expansion at a rate of
approximately 10 Celsius per 1000 meters until
saturation. If air continues to rise beyond the
lifting condensation level, it cools at the wet
adiabatic lapse rate (WALR). Because water vapor
condenses out of the rising air, temperature and
dew-point temperature both decrease at the wet
adiabatic lapse rate to the top of the mountain,
and relative humidity remains at 100. As air
sinks on the leeward side of the mountain, its
temperature increases at the dry adiabatic lapse
rate and its dew-point temperature increases at
2 C per 1000 meters.
MATERIALS METHODS Materials used for obtaining
the data were a compass, 3 rain gauges, and 3
large, same-sized containers. During October
17-31, 2003, a two-week research was performed.
Three gages were set up along a transect line. In
setting up this experiment, locations were
decided by appropriate elevation heights and was
determined by using a compass. The three
different heights were chosen based on the idea
of the orographic uplift effect which would
allegedly deposit higher amounts of rainfall at
higher elevations of the windward side of a
mountain. Similar cover and forested types along
the transect were used so the differences in
canopy interception loss would not influence the
data. Three rain gages were set up along a
transect line on the windward side of the
mountain, one at each elevated location.
RESULTS Data were collected during the
two-week time period. From the data, we plotted
the amount of rainfall in inches as compared to
its corresponding elevation increase.
The values in Figure 1 shows an upward trend
as elevation increases then rainfall amounts
increase. Figure 2 shows the comparison of
yearly rainfall average between Tully, N.Y.
located in the valley of Heiberg Forest and the
highest elevation in the adjacent Heiberg Forest.
The data, collected by others, clearly show a
pattern of significantly more rainfall for 11 of
the 12 months.
FIGURE 2 - COMPARISON OF TOTAL AVERAGE RAINFALL
BY MONTH FOR TULLY, NY AND HEIBERG FOREST
I C N H E S
FIGURE 1 - RAINFALL AMOUNTS FOR OCTOBER 17-31,
2003
Note Weather Station, Tully Heiberg Forest,
Cortland County is at about 4246N 7605W.
Height is about 578 m/1896 feet above sea level.
DISCUSSION CONCLUSION Orographic Uplift occurs
in where a moist maritime air mass encounters a
mountain front. The air mass is then forced to
rise. As the air mass rises it cools, reaches
100 humidity, and releases moisture as
precipitation. Precipitation falls on the upwind
side of mountains and little precipitation falls
on the downwind (or lee) side of mountains. Areas
that are located far inland from large water
bodies have less precipitation because much of
the moisture in the atmosphere has already been
dropped on intervening mountainous regions. In
conclusion the simplistic data seems to support
the alternative hypothesis and to reject the null
hypothesis. In future studies to better
determine, wind speeds and temperature data may
also influence results along with many more
random samples taken over a period of
years. REFERENCES Climate History for A
Cooperative Observer Location
http//www.erh.noaa.gov/er/bgm/coop Records and
Averages, Tully, New York http//weather.yahoo.
com/climo/USNY1462f.html Carbone, G. Exercises
for Weather Climate, 4th Edition, Prentice
Hall, 2001 Ahrens, C.D., Meteorology Today 7th
Edition, Brooks/Cole Publishing, CA, 2003.
I C N H E S
ELEVATION IN FEET
Note Based on Weather Station, Tully Heiberg
Forest Data, Average rainfall at 1900 feet for
Heiberg Forest for Oct 17-31 (1967-1995) is
2.73Inches